Octopuses (and Their DNA) Suggest Antarctica Will Melt Again

By atlasobscura.com.

DID THE WEST ANTARCTIC ICE Sheet completely collapse during the latest interglacial period, about 125,000 years ago? It’s an important question for climate scientists, but geology was giving them no answers. So they turned to genetics instead.

Enter Turquet’s octopus (Pareledone turqueti), a cephalopod with a four-million-year pedigree that makes its home in the icy waters around Antarctica. Recent DNA analysis shows that two distinct populations of this species, one in the Weddell Sea and the other in the Ross Sea, mated about 125,000 years ago.

This could only have happened if the massive ice sheet that now separates those populations wasn’t there at the time. So yes, it did collapse. And that’s bad news, because it increases the likelihood that it will happen again.

The Importance of Antarctic Ice

While ice is melting at both poles, the situation in the Antarctic is much more dramatic. The North Pole is just a relatively thin layer of frozen water that expands and contracts with the seasons—its volume ranging from a few hundred thousand to a few million cubic kilometers (several hundred thousand cubic miles). Scientists predict the Arctic could be entirely ice-free in summer by 2035 and year-round by 2050. At that point, there will just be open ocean at the top of the world.

The South Pole, in contrast, has a solid foundation, upon which rests a thick ice layer up to several kilometers (a couple of miles) deep. In all, Antarctica holds 26.5 million cubic kilometers (6.4 million cubic miles) of ice, which represents about 90 percent of the world’s total ice volume.

That abundance of ice obstructs our view of the continent beneath, which is much smaller than what currently appears on our maps—a vast white blob with a small tail.

Read more at atlasobscura.com.